The White House Conference on Aging (1971) has recently focused much attention on the nutritional needs of the elderly, citing impairment of taste and smell as one of the major factors leading to an inadequate diet. Research done during this grant indicates a substantial loss in food recognition and smell discrimination by the aged. The proposed research is aimed at further investigating the sensory qualities of gustation and olfaction, especially as they change during the aging process. Thresholds for odors and tastes of nutrients and other stimuli will be determined over the life-span. Nutrients and foods will also be ordered by multidimensional scaling procedures on the basis of their tastes and smells to investigate qualitative changes with age. Multidimensional scaling procedures have the advantage of being open-ended so they can arrange stimuli without a priori knowledge of categories. It is virtually impossible to order most food substances (e.g. roast beef), spices, and nutrients by phenomenological means into the traditional qualitative gustatory categories of sweet, sour, salty, and bitter. Subjects will be tested throughout the life-span. At the very least, the methodology of multidimensional scaling, as applied here, will yield multidimensional spaces which illustrate meaningful relationships and distances among taste and smell stimuli revealing how these relationships change with age. It will also deepen our understanding of both psychological and physical dimensions underlying the experience of taste and smell. Attention will be focused on understanding the underlying receptor process as well and how it changes with age.